LU-1600 lnet: another race in lnet_nid2peer_locked

LU-1600 lnet: another race in lnet_nid2peer_locked

We fixed a race for the case that LNet is shutdown while the second
thread is in progress of creating a peer, but there is another race
if LNet is shutdown _before_ lnet_nid2peer_locked is called by the
second thread, for example: called from lnet_parse() by LND thread,
in this case, we should return error w/o trying to create peer,
otherwise the shuttingdown thread could think peer-table is empty
and move to the next step with leaving a peer on deathrow list.

This patch also passed error code into lnet_finalize() when it's
called from lnet_drop_delayed_msg_list, otherwise lnet_finalize()
will treat the message as a complete message and hit assertion
because the message is actually incomplet.

We also did some coding style cleanup in this patch.

Signed-off-by: Liang Zhen <liang@whamcloud.com>
Change-Id: I445298d639173840687412b11da41006ddc20c10
Reviewed-on: http://review.whamcloud.com/3369
Tested-by: Hudson
Reviewed-by: Bobi Jam <bobijam@whamcloud.com>
Reviewed-by: Doug Oucharek <doug@whamcloud.com>
Tested-by: Maloo <whamcloud.maloo@gmail.com>
Reviewed-by: Oleg Drokin <green@whamcloud.com>